Stranding machine

ABSTRACT

An accumulator stranding machine for twisting strands at a reversing twist, wherein the stranding nipple moves in unison with the strands, towards the accumulator whenever the accumulator changes speed; the stranding nipple moves in the opposite direction during regular rotation of the accumulator.

United States Patent Stoebener 51 Feb. 29, 197 2 [54] STRANDING MACHINE3,052,079 9/1962 Henning ..57/34 [72] Inventor: Roll Stoebener,Hannover, Germany n31 Assignee: Kabel-und Metallwerlte Gutehoiigi g: aw2322:? Ak'iengeseu'chm Hanmve" 3,507,108 4/1970 Yoshimura et al ..57/34[22] Filed: May 8, 1970 Primary Examiner-Stanley N. Gilreath AssistantExaminerWemer H. Schroeder [21] Appl' 35357 Au0mey-Smyth, Roston &Pavitt [30] Foreign Application Priority Data [57] ABSTRACT Anaccumulator stranding machine for twisting strands at a May 1969 Germany19 24 0934 reversing twist, wherein the stranding nipple moves in unisonwith the strands, towards the accumulator whenever the accu- US. Cl-..57/34 AT, mulator changes peed; the stranding moves in the p. l l l ClJ10 b H0 1 b 4 posite direction during regular rotation of theaccumulator.

[58] Field of Search ..57/34, 34 AT, 59, 60, 62, 63,

57/64 9 l y 94 4 Claims, 2 Drawing Figures [56] References Cited UNITEDSTATES PATENTS 3,025,656 3/1 962 com; 7@4

l l l 1a leregnel flr/re J4 #e/e/J/ZA Patented Feb.29,1972 v 3,645,079

STRANDING MACHINE V The present invention relates to a stranding machinewith accumulator storage facilities and provided for twisting plural,individual strands or groups of strands.

US. Pat. No. 3,169,360 discloses a stranding machine using tworelatively large rolls for accumulating and temporarily storingthestrands. A pair of stranding nipples is provided, each-comprised of apair of pinch rolls. One pair of pinch rolls is disposed at the entranceto the accumulator, the other pair is located at the exit or withdrawalside thereof. The accumulatoriis mounted in a cradle. As strands arepaid off a supply, they. pass between the pinch rolls of the first pairand are wound upon the accumulator. The cradle rotates about an axis inthe propagation path of the strands, so that they are twisted downstreamfrom the entrance side pinch rolls and along the path leading therefromto the accumulator. The axis of rotation of theaccumulator is, thus, thestranding axis of twisting. The exit sidepinch rollstwist strandsleaving the accumulator, but at opposite twist.

,More. particularly, the cradle actually rotates about the twisting orstranding axis and halts in alternating sequence. A period of rotationis followed by an equally long period without rotation. .Untwistedstrands are wound upon the rolls of the accumulator when halting whilepreviously twisted strands leave the accumulator without untwisting. Asall of the previously twisted strands arewithdrawn from the accumulator,the latter has been filled with untwisted strands inthe meantime.Thereupon the cradle rotates and untwisted strands are paid off theaccumulator and pass through the exit side pinch rolls. The strandsdrawn off the accumulator are twisted opposite to twisting impartedconcurrently upon strands passing through the entrance side pinch rollsand towardthe accumulator.

. The purpose of this arrangement is to provide periodically reversingtwist for the stranded product, the reversal point of thetwist beingspaced apart by a distance that is given by the capacity of theaccumulator. Such twist reversal will also be produced if theaccumulator alternates its direction of rotation/about the strandingaxis. In this case, only one stranding nipple, for example, one pair ofpinch rolls is needed.

A problem arises when the cradle slows down to-stop and when itstarts upagain, while strands are continued to pass into the machine. In eithercase, there is partial or complete untwisting of strands as extendingbetween accumulator and either .pair of pinch rolls. Thus, the systemfails to establish definite-points along the stranded material where thetwist reverses; instead the finished product has lengthy portions ofconsiderable slack, where the strands have been gradually untwisted,respectively followed by rather loosely twisted strands in the oppositedirection. In fact then, there is a lengthyportionwithout significanttwist. The same problem arises, if the accumulator does not alternatebetween rotation and halting periods butalternates as to its directionof rotation about the stranding axis. It should be mentioned, thatbinding of.;the twist reversingpoints has nothing to do with theinherentproduction of a loose twist during slowdownperiods of the accumulator.

It has been suggested to provide freely, rotatable guide sheaves in theplane of the axis of rotation of the accumulator; the sheaves rotatewith the accumulator. about its: axis ;-(their axes are transverse tothe stranding axis). The sheaves are disposed close to the entrance ofthe accumulator so thatthe distance between the point of the strandingmachine closest to the stranding nipple and undergoing rotation aboutthe stranding axis is shortened. Accordingly, untwisting affects ashorter length of strand only. Nevertheless, it was found that thestranded product is still partially untwisted over significant lengths.This partial or even complete untwisting is to some extent dependentupon the speed of reversal or halting of the cradle of the accumulator,but the controlling factor is still the distance between accumulator andstranding nipple.

The problem to be solved, therefore, relates particularly to ofreversing twist. The stranding machineimproved in accordance with theinvention includes a strand accumulator, for example, as aforedescribed,and which has phases of particular rotation relative to a strandingnipple, about the stranding axis, alternating with phases of differentrotation corresponding to the ultimate production of reversed twist.Transition phases are interspaced, each extending, for example, frombeginning of terminating a phase of particular rotation to completion ofestablishing the next phase of different rotation. One of the phases ofdifferent rotation may be equivalent to zero rotation, or the twodifferent phases of rotation may merely differ in the direction ofrotation at particular speed. In the latter case, only one strandingnipple is needed, for example, at the entrance of the accumulator. Atransition phase is, thus, the period from the beginning of a drop inspeed of the accumulator about the stranding axis up to complete haltingor up to completion of accumulator reversal.

In accordance with a particular feature of the invention, the strandingnipple moves at relatively slow speed during each of the principlephases, away from the accumulator entrance along the stranding axis,while during the transition phase the stranding nipple moves towards theaccumulator, together with the propagation of the strands. If thestranding nipple is disposed at the entrance of accumulator it shouldmove at the samespeed as the strands during each transition phase. Thus,during the transition phase there is no (or hardly any) relative motionbetween stranding nipple and strands. There is an apertured guide platein front of the stranding nipple guiding the several strands as they arepaid off their respective supply. This guide plate is to move in unisonwith the stranding nipple along the stranding axis as described. As aconsequence of the motion of the nipple towards the accumulator duringslowdown and speedup phases thereof, production of lengthy portionwithout anyor with insufficient twist is avoided.

While thespecificationconcludes with claims particularly pointing outanddistinctly claiming the subject matter which is regarded as theinvention, it is believed that the invention, the objects and featuresof the invention and further objects, features and advantages thereofwill be better understood from the following description taken inconnection with the accompanying drawings in which:

FIG. 1 illustrates somewhat schematicallya side view of a strandingmachine improved in accordance with the preferred embodiment of theinvention; and

FIG. 2 illustrates an operational speed diagram plotted in relation toparticular phases of operation of the improved structure as shown inFIG. 1.

Proceedingnow to the detailed description of the drawings, in FIG.lthereof there is shown an accumulator comprised of two sets of wheels,1 and 2 suitably journaled on a hollow tubular shaft3 but at rightangles to the axis 31 thereof. Shaft 3 has a lateral slot 3a, anentrance opening 3b, and an exit opening 30. Twisted strand 10 entertubular shaft 3 at opening 3b, pass through the tube towards slot 3a.Suitable guide means pass the strand through theslot for accumulation onthe set of wheels 1 and 2 and thence back through slot 30 into hollowshaft 3 to propagate again along axis 31 for withdrawal from exit 3c andto be wound upon a drum or the like.

Hollow, tubular shaft 3 is journaledin bearing blocks 4 and 5, and,asschematically indicated, areversible drive 30 imparts rotation uponthe shaft about the central axis 31. Guide sheaves ,7 are journaled upona carrier-6 that extends axially from hollow shaft 3 near entrance 3bthereof. The sheaves run the stranded product 10 from a point 7a on axis31 of rotation of shaft 3 along a meandering path, back into the axis31, adjacent opening 3b. The point 7a can actually be regarded as thestranding-point and may, thus, constitute the entrance of theaccumulator.

Individualstrands 12 are paid off and advanced from supply drums,reelsor the like (not shown) and pass through apertures in a plate or disk 8.The disk 8 is mounted on a support 13which can alsov be termed acarriage. A stranding nipple 9 is likewise,mounted. on carriage 13 andis particularly positioned to have its operating point onaxis 31-. Also,disk 8 has its aperturespreferably.arrangedsymmetrical to axis 31.

During operation, strands 12 advance continuously through disk 8 and tostranding nipple 9 so as to propagate further on axis 31 until reachingpoint 7a. Concurrently. the accumulator assembly' 1, 2 and 3. includingalso elements 6 and 7, rotates about axis 31, thereby twisting thestrands 12. The strands are twisted particularly between nipple 9 andpoint 70. The length of that path from head 9 to point 70, the speed ofrotation of the accumulator and the speed of propagation of the strands,determine the extent of twisting. The accumulator continues to rotateabout axis 31 until filled, whereupon its direction of rotation isreversed, and the previously twisted strands are now withdrawn while thestrands, reeled onto the accumulator, are twisted in the oppositedirection, etc. Withdrawal equipment (not shown) on the exit side of theaccumulator inhibits untwisting of stranded product.

In FIG. 2, AT denotes generally the periods during which the accumulatorrotates at constant speed, and in either direction. Thus, each of theseperiods AT defines one of the main phases mentioned above. At marks thetransition periods, beginning, for example, at a time T1 when theaccumulator begins to slowdown. A transition period ends when theaccumulator has reached rated speed in the opposite direction, such asat time T2. During this transition period At strands 12 continue topropagate into the machine. Take the instant Tl, at that time thestrands between stranding nipple 9 and point 711 are in a particularstate of twisting. As rotation declines, twisting is reduced, partiallyundone, before twisting in the opposite direction is resumed at fullspeed, so that without further measure a considerable length of strandsis only partially twisted or not at all.

ln accordance with the invention, disk 8 and stranding nipple 9 aremounted on carriage 13 which is displaceable on a bed or pathway 14 formovement parallel to axis 31, so that stranding nipple 9 remains on thataxis, The carriage is moved by a controlled drive 15, which positionscarriage 13 and particularly the stranding nipple 9 thereon inaccordance with the following rules.

Vertical dash-dot lines in FIG. 1 denote three different positions forstranding nipple 9, respectively A, B and C. The stranding nipple 9 isillustrated to be currently in position C. During a main phase ofconstant speed rotation of accumulator assembly 1, 2, 3, 6, 7, in eitherdirection, drive 15 moves carriage 13 so that stranding nipple 9 isgradually displaced from position B to position C. Thus, the strandingnipple recedes slowly from point 7a, and from the accumulator ingeneral. Upon reaching point C, drive 15 stops, but that instantcoincides with a time slowdown of the accumulator rotation begins.Therefor a transition phase begins. FIG, 2 illustrates the time-speedcharacteristic of the accumulator, and as stated above, slowdown beginsat time T1 when nipple 9 is in position C while full speed in thereverse direction is reached at T2.

Concurrently to the accumulator reversing its rotation, drive 15 movescarriage 13 so that stranding nipple 9 moves from point C back to pointB. In particular, nipple 9 moves at the speed of propagation of thestrands 12. At first stranding nipple 9 moves from point B to midpointA. Concurrently thereto, the accumulator assembly reduces its speedbefore actually halting momentarily when nipple 9 arrives at point A.During this period the twisting length between nipple 9 and point 70 hasgradually shortened. Thus, even though the rotation of the accumulatorproducing the twist is reduced, the strands that passed through point 7ainto the accumulation will be completely twisted.

As the nipple reaches point A the accumulator actually halts and thereis a remaining length of strands between nipple 9 in position A andpoint 70. It was found that length has actually been twisted more thannormal. As nipple 9 continues to move towards point B, the accumulatoraccelerates for rotation in the opposite direction. The stronger twistpreviously obtained is now partially undone, so that the product nowentering the accumulator is actually about normally twisted. As nipple 9arrives at position B a rather instantaneous change in twist occursaffecting only the small len th between stranding nipple 9 when inposition B and point a.

The accumulator has reached rated speed when nipple 9 arrives atposition B. Thereafter, carriage 13 recedes slowly to position C for thestranding nipple, as the accumulator rotates regularly.

Position C is, of course, spaced apart from position B by a distancewhich is at least approximately equal to the speed of strand propagationdivided by the duration of the transition period At, which is the periodrequired for completing reversal of rotation of the accumulator. On theother hand, reversible carriage drive 15 should be adjusted to recedefrom position B to position C at such a speed that the period it takesis equal to the period required to fill the accumulator with strandstwisted in one particular direction. This is not too critical, but forreasons of avoiding irregular stranding lay this latter rule should beobserved.

In order to avoid lateral whipping of the strands as they extend betweenstranding nipple 9 and stranding point 7a, particularly when thestranding nipple is rather far from that point 7a, it may be advisableto provide bracketlike elements 11, which fold back when strandingnipple 9 approaches. As stranding nipple 9 recedes they gradually foldup and provide short guide ducts or tunnels for the strands. Theseelements 11 may be operated mechanically, hydraulically or electrically,for example, in response to sensing switches on bed 14, responding tothe position of carriage l3 thereon.

The invention is not limited to the embodiments described above but allchanges and modifications thereof not constituting departures from thespirit and scope of the invention are intended to be included.

1. In a stranding machine which includes an accumulator for strands,further including means for rotating the accumulator on a strandingaxis, and at different particular speeds, there being transition periodsduring speed changes, there being additionally means for paying strandsto be twisted, the improvement comprising:

a stranding nipple disposed for positioning and running the strands tobe twisted into the axis, to obtain twisting of the strands uponrelative rotation between the accumulator and the stranding nipple aboutthe axis; and

means for moving the stranding nipple towards the accumulator on thestranding axis and at least approximately during each transition period,said means moving the stranding nipple in the opposite direction on theaxis during periods of rotation of the accumulator at each of theparticular speeds.

2. Stranding machine as in claim 1, means for operating the means formoving the stranding nipple towards the entrance of the accumulator atessentially similar speed as the pay-in speed of the strands and duringeach of the transition periods, said operating means positioning thenipple close to the entrance of the accumulator at the end of eachtransition period.

3. Stranding machine as in claim 1, there being a guide plate withplural apertures for guiding individual strands towards the strandingnipple, the guide plate disposed for moving in unison with the nipple.

4. Stranding machine as in claim 1, there being displaceable strandguiding means disposed between nipple and accumulator.

1. In a stranding machine which includes an accumulator for strands,further including means for rotating the accumulator on a strandingaxis, and at different particular speeds, there being transition periodsduring speed changes, there being additionally means for paying strandsto be twisted, the improvement comprising: a stranding nipple disposedfor positioning and running the strands to be twisted into the axis, toobtain twisting of the strands upon relative rotation between theaccumulator and the stranding nipple about the axis; and means formoving the stranding nipple towards the accumulator on the strandingaxis and at least approximately during each transition period, saidmeans moving the stranding nipple in the opposite direction on the axisduring periods of rotation of the accumulator at each of the particularspeeds.
 2. Stranding machine as in claim 1, means for operating themeans for moving the stranding nipple towards the entrance of theaccumulator at essentially similar speed as the pay-in speed of thestrands and during each of the transition periods, said operating meanspositioning the nipple close to the entrance of the accumulator at theend of each transition period.
 3. Stranding machine as in claim 1, therebeing a guide plate with plural apertures for guiding individual strandstowards the stranding nipple, the guide plate disposed for moving inunison with the nipple.
 4. Stranding machine as in claim 1, there beingdisplaceable strand guiding means disposed between nipple andaccumulator.